Teresa Sanchez Cepeda Davila y Ahumada, born at Avila, Old Castile, 28 March, 1515; died at Alba de Tormes, 4 Oct., 1582. The third child of Don Alonso Sanchez de Cepeda by his second wife, Doņa Beatriz Davila y Ahumada, who died when the saint was in her fourteenth year, Teresa was brought up by her saintly father, a lover of serious books, and a tender and pious mother. After her death and the marriage of her eldest sister, Teresa was sent for her education to the Augustinian nuns at Avila, but owing to illness she left at the end of eighteen months, and for some years remained with her father and occasionally with other relatives, notably an uncle who made her acquainted with the Letters of St. Jerome, which determined her to adopt the religious life, not so much through any attraction towards it, as through a desire of choosing the safest course. Unable to obtain her father's consent she left his house unknown to him on Nov., 1535, to enter the Carmelite Convent of the Incarnation at Avila, which then counted 140 nuns. The wrench from her family caused her a pain which she ever afterwards compared to that of death. However, her father at once yielded and Teresa took the habit.

After her profession in the following year she became very seriously ill, and underwent a prolonged cure and such unskillful medical treatment that she was reduced to a most pitiful state, and even after partial recovery through the intercession of St. Joseph, her health remained permanently impaired. During these years of suffering she began the practice of mental prayer, but fearing that her conversations with some world-minded relatives, frequent visitors at the convent, rendered her unworthy of the graces God bestowed on her in prayer, discontinued it, until she came under the influence, first of the Dominicans, and afterwards of the Jesuits. Meanwhile God had begun to visit her with "intellectual visions and locutions", that is manifestations in which the exterior senses were in no way affected, the things seen and the words heard being directly impressed upon her mind, and giving her wonderful strength in trials, reprimanding her for unfaithfulness, and consoling her in trouble. Unable to reconcile such graces with her shortcomings, which her delicate conscience represented as grievous faults, she had recourse not only to the most spiritual confessors she could find, but also to some saintly laymen, who, never suspecting that the account she gave them of her sins was greatly exaggerated, believed these manifestations to be the work of the evil spirit. The more she endeavoured to resist them the more powerfully did God work in her soul. The whole city of Avila was troubled by the reports of the visions of this nun. It was reserved to St. Francis Borgia and St. Peter of Alcantara, and afterwards to a number of Dominicans (particularly Pedro Ibaņez and Domingo Baņez), Jesuits, and other religious and secular priests, to discern the work of God and to guide her on a safe road.

- Clissold, Stephen. St Teresa of Avila. London, England 1979: Sheldon Press.- Du Boulay, Shirley. Teresa of Avila. London, England 1991: Hodder and Stoughton.- Lincoln, Victoria. Teresa: a Woman. New York 1984: State University of New York Press, Albany.- Teresa of Avila. The Life of Teresa of Jesus. New York 1991: Doubleday.- Teresa of Avila. The Interior Castle. New York 1979: Paulist Press.- Teresa of Avila, The Collected Works of Teresa of Avila, 3 vol., (Washington: Institute of Carmelite Studies, 1976)